This invention relates generally to the art of pipe networks for buildings, and especially to apparatus and systems for making pipe networks fire retardant.
For a number of years, pipe networks which have extended through floors of buildings have been made fire retardant by encircling pipes with fire-stop intumescent material which expands upon contact with heat to close the pipes at the floors. It has been suggested to do this by encircling a pipe with a metal container enclosing intumescent material and fastened to a bottom surface of a floor through which the pipe passes. However, a difficulty with such a suggested system is that the intumescent material must normally be installed separately from the pipe and normally must be put in place after a pipe string has been extended through a hole in a floor. Thus, it is an object of this invention to provide an under-floor fire-stop coupling which can be installed at the same time a pipe string is assembled.
Other suggestions have been made for casting pipe couplings having intumescent collars wrapped thereabout into concrete floors when they are poured. Such "cast-in" intumescent collars work quite well with some cast-in couplings, however, other cast-in coupling have outwardly projecting flanges on the lower ends thereof which are used for fastening the couplings to concrete forms. Such flanged cast-in couplings cannot be properly combined with cast-in intumescent fire stop collars because these flanges inhibit heat from reaching the collars. Thus, it is another object of this invention to provide a fire stop adaptor which can be used with "cast-in" couplings that do not have cast-in intumescent fire stop collars mounted thereon.
One problem with many prior-art fire-stop intumescent material collars is that workmen must form them at job sites, which is inconvenient. It is therefore an object of this invention to provide a pipe coupling adaptor with an intumescent collar which can be prepackaged prior to being transported and sold.
It is a further object of this invention to provide a fire-stop pipe coupling adaptor which is easy and relatively inexpensive to construct, but yet which is durable and effective in responding to heat.